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991.
In a cement plant, the preparation of on-target, uniform kiln feed requires certain tasks to occur in unison. Typically, this involves stockpiling/preblending, proportioning, grinding, and stocking/blending. The raw-mix logic of a plant describes the type and layout of equipment used to perform these tasks. The capital and operating cost vary, in part, according to the choice of raw-mix logic. Many factors, especially the reliability of the supply and chemistry and the handling characteristics of raw materials, will affect the choices made in conceiving a raw-mix logic. The increasing availability of the sensors discussed gives plant designers and operators opportunities to reduce capital and operating cost and/or improve, as indicated by the regularity of kiln feed, system performance. Diminishing the size and complexity of blending and stocking equipment before and after the raw mill represents a common strategy for reduction of capital and operating cost. The paper discusses the choice between X-ray fluorescence (XRF) and γ-ray analysis sensors. Cross belt analysers used in the stockyard are also discussed 相似文献
992.
Formation of disinfection by-products (DBPs) can be controlled by removal of disinfection by-product precursors before disinfection. Variable success has been reported, depending on the treatment used and water tested. Chemical and biological oxidations are candidate technologies to control DBP formation. Given the uncertainty over the identity of DBP precursors, the use of surrogates of natural organic matter (NOM) allows fundamental probing of the links between compound character, removal and DBP formation. Nine compounds were chosen to represent NOM and their removal by two advanced oxidation processes (AOPs), UV-C irradiation and biological treatment compared while haloacetic acid (HAA) formation before and after treatment was measured. Although AOPs were able to fully remove all compounds, incomplete mineralisation led to increased HAA levels, dramatically in the case of two amino acids. Biological treatment was effective in removing amino acids but also moderately increased the HAA formation potential (HAAFP) of hydrophilic compounds. These findings indicate waters with high amino acid concentrations will be susceptible to raised HAA levels following AOP treatment and careful process selection for HAA control is required in such cases. 相似文献
993.
MacDougal M.H. Geske J. Chao-Kun Lin Bond A.E. Dapkus P.D. 《Photonics Technology Letters, IEEE》1998,10(1):15-17
The authors have measured the thermal impedance of vertical-cavity surface-emitting lasers (VCSELs) with oxide/GaAs DBRs and shown that it is comparable to that of VCSELs with all-semiconductor DBRs. A VCSEL with an 8-μm oxide aperture shows a thermal impedance of 2.8°C/mW. By varying the aperture size, the thermal conductance of the material below the active area is 0.255 W/cm°C. These results demonstrate that the oxide is not a major barrier to heat transport out of the active region 相似文献
994.
Breakage and growth towards a stable aerobic granule size during the treatment of wastewater 总被引:2,自引:0,他引:2
To better understand granule growth and breakage processes in aerobic granular sludge systems, the particle size of aerobic granules was tracked over 50 days of wastewater treatment within four sequencing batch reactors fed with abattoir wastewater. These experiments tested a novel hypothesis stating that granules equilibrate to a certain stable granule size (the critical size) which is determined by the influence of process conditions on the relative rates of granule growth and granule breakage or attrition. For granules that are larger than the critical size, granule breakage and attrition outweighs granule growth, and causes an overall reduction in granule size. For granules at the critical size, the overall growth and size reduction processes are balanced, and granule size is stable. For granules that are smaller than the critical size, granule growth outweighs granule breakage and attrition, and causes an overall increase in granule size. The experimental reactors were seeded with mature granules that were either small, medium, or large sized, these having respective median granule sizes of 425 μm, 900 μm and 1125 μm. An additional reactor was seeded with a mixture of the sized granules to represent the original source of the granular sludge. The experimental results were analysed together with results of a previous granule formation study that used mixed seeding of granules and floccular sludge. The analysis supported the critical size hypothesis and showed that granules in the reactors did equilibrate towards a common critical size of around 600–800 μm. Accordingly, it is expected that aerobic granular reactors at steady-state operation are likely to have granule size distributions around a characteristic critical size. Additionally, the results support that maintaining a quantity of granules above a particular size is important for granule formation during start-up and for process stability of aerobic granule systems. Hence, biomass washout needs to be carefully managed to optimize granule formation during the reactor start-up. 相似文献
995.
We have found that the early response of axotomized rat retinal ganglion cells is characterized by the differential regulation of a number of fast axonally transported proteins. The abundance of 23 radiolabeled fast transported proteins was analyzed at 2 and 5 days after axotomy using two-dimensional gel electrophoresis. Corresponding changes in retinal GAP-43 mRNA were measured using northern analysis. Within 2 days of injury, > 40% of the transported proteins analyzed, including GAP-43, showed increased labeling above control levels. Approximately 13% of transported proteins decreased below control levels, whereas the remainder did not change. Five days after axotomy, only GAP-43 and another fast transported protein, C3, continued to sustain measurable increased labeling above control levels; all previously elevated proteins appeared to have been down-regulated by this time, which corresponds to the onset of cell death. These differential changes were accompanied by parallel increases in GAP-43 mRNA. These results suggest that the molecular changes within rat retinal ganglion cells are differentially regulated within two stages subsequent to damage, initial regenerative growth followed by cell death. 相似文献
996.
The authors describe the relationship between service intensity and staffing, organizational, client, and site characteristics in 19 programs based on the Thresholds Bridge adaptation of the assertive community treatment (ACT) model. Pearson correlations were examined between 14 program characteristics and intensity of ACT services. Several staffing and organizational attributes were related to service intensity: larger team size, shared caseloads, greater supervisor involvement in direct client services, and assignment of primary responsibility for the client to the team. The potential facilitating relationship between several aspects of team operation and intensive services is discussed as are implications for local implementation of ACT. 相似文献
997.
998.
AE Chang A Aruga MJ Cameron VK Sondak DP Normolle BA Fox S Shu 《Canadian Metallurgical Quarterly》1997,15(2):796-807
PURPOSE: In preclinical studies, we have reported the ability to induce immune T cells in lymph nodes (LN) primed by in vivo vaccination with tumor cells admixed with a bacterial adjuvant. These LN cells can be activated and expanded ex vivo for the successful immunotherapy of established tumors. We have applied these methods to generate vaccine-primed LN in patients with advanced melanoma and renal cell cancer (RCC) for therapy. MATERIALS AND METHODS: Irradiated autologous tumor cells admixed with bacille Calmette-Guérin (BCG) were used to vaccinate patients. Seven days later, draining LN were removed for activation with anti-CD3 monoclonal antibody (mAb) followed by expansion in interleukin-2 (IL-2). Activated LN cells were administered intravenously (IV) with the concomitant administration of IL-2. RESULTS: A total of 23 patients were evaluated (11 melanoma and 12 RCC). Vaccine-primed LN were expanded ex vivo with a mean of 8.4 x 10(10) cells administered per patient. Among 20 patients assessed, 15 demonstrated minimal cytotoxicity of autologous tumor cells by the activated LN cells, with the remaining mediating nonspecific cytotoxicity. By contrast, a majority of the activated LN cells showed highly specific release of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon gamma (IFN-gamma) to autologous but not allogeneic tumor stimulation. This tumor-specific cytokine release was found to be major histocompatibility complex (MHC) class I-restricted, which indicates the involvement of CD8+ cells. Among 11 melanoma patients, one had a partial tumor response. Among 12 RCC patients, two had complete and two partial responses. A trend (P = .066) between the enhancement of delayed-type hypersensitivity (DTH) reactivity to autologous tumor after therapy and tumor regression was observed. CONCLUSION: Tumor vaccines can be used to induce immunologically specific T-cell responses against melanoma and RCC in draining LN. Anti-CD3/IL-2 activation of primed LN cells can be reliably performed for clinical therapy and appears to have activity in patients with metastatic RCC. 相似文献
999.
1000.
There are several successful operating systems for mini-computers written in high level languages and the time is now ripe for the development of portable systems for such machines. The system described in this paper is primarily designed to provide a friendly interactive multiprocessing environment for a single user. From his point of view, substantial parts of the system are completely machine independent. These include, for instance, the filing system, the command language, text editors, overlaying facilities and interprocess communication primitives. The system is suitable for many different application areas ranging over process control, data acquisition, data communication, text handling, data base systems and teaching. 相似文献